1. Technical Field
The disclosure generally relates to a method for grouping Machine-type-communication (MTC) devices in MTC networks.
2. Related Art
Machine-type-communication (abbreviated as MTC) or Machine to Machine communications (M2M) can enable information exchange between a subscriber station (or a wireless communication device) and a server in the core network (through a base station) or just between subscriber stations, which may be carried out without any human interaction. MTC would have huge market potential. However, when numerous MTC devices are concurrently transmitting/delivering messages to wireless communication networks, it may easily result in radio access network (RAN) congestion/overload, and further result in core network (CN) congestion/overload. For example, in a 3GPP LTE network, CN congestion/overload may occur at mobility management entity (MME), femtocell gateway, serving general packet radio service support node (Serving GPRS support node, abbreviated as SGSN), Gateway GPRS support node (GGSN), MTC gateway (MTC GW), or MTC server. CN congestion/overload may further cause unacceptable delay of messages or packet loss of all services within the wireless communication networks.
Though conventional art proposes several approaches to mitigate the RAN overload or the CN overload, such as call admission control approaches, active paging-based grouping and time control approaches, access probability adaptation approaches or access class barring (ACB) schemes, there is no effective approach which could mitigate both the RAN overload and the CN overload at the same time.
On the other hand, heterogeneous MTC network, which consists of macro cell MTC devices and femto cell MTC devices, could be applied to mitigate the RAN overload. For example, MTC devices within houses or buildings could be served by femto cell base stations (the femto cell stations are connected to the MTC server through other Internet connections rather than through conventional RAN) while outdoors MTC devices are served by macro cell base stations. Although femto cell MTC devices consume less power and femto cell base stations offload MTC message traffic from macro cell base stations, the CN overload is not mitigated properly and may become worse since there might be more MTC devices connected to the MTC servers through the femtocell base stations. Therefore, it is a major concern in the wireless communication industry to develop an effective access scheme for heterogeneous MTC network.